The invention relates generally to apparatuses and methods for cutting sheet material and deals more particularly with an apparatus and related method for cutting and dedusting piled or fleecy material, such as velour.
Automatic cutting apparatuses and methods are widely used today in the garment, automobile and furniture industries where much fabric is cut. Many of the cutting apparatuses are numerically controlled and are capable of cutting large quantities of pattern pieces from layups of sheet material with high speed and accuracy. For example, numerically controlled cutting apparatuses are shown in U.S. Pat. Nos. 3,955,458 issued Sept. 17, 1973; 3,830,122 issued Aug. 20, 1974; and 4,091,701 issued May 30, 1978; each to Pearl and assigned to Gerber Garment Technology, Inc. of East Hartford, Conn. and hereby incorporated by reference as part of the present disclosure. Such numerically-controlled apparatuses may include a vertically-mounted reciprocating cutting blade, a horizontal bed for supporting the layup and a computer programmed to direct the cutting blade to cut the layup along a desired path to form the pattern pieces.
To insure cutting accuracy, it is often advantageous to positively affix the layup to the support bed while the layup is being cut and, if possible, compress the layup as disclosed in U.S. Pat. Nos. 3,495,492 issued Feb. 17, 1970; 3,790,154 issued Feb. 5, 1975; and 3,765,289 issued Oct. 16, 1973; each to Gerber et al and assigned to Gerber Garment Technology, Inc., and hereby incorporated by references as part of the present disclosure. As further disclosed in these patents, the layup may be covered with a substantially air-impermeable sheet, and a vacuum may be applied to the underside of the air-impermeable sheet to draw the impermeable sheet toward the support bed to fix and compress the layup while it is being cut.
As an alternative to the vacuum holddown system described above, U.S. Pat. Nos. 2,897,424 and 2,897,425 to Waring disclose an electrostatic holddown system for a cutting apparatus.
Problems have emerged in the cutting of layups of piled or fleecy material, such as velour or velvet made of a carrier sheet and pile fibers attached at one end to the carrier sheet, especially when the layups are compressed during cutting and the pile fibers have a significant length, such as one-thirty-second to one-eighth of an inch or more. During such compression, each work sheet is flattened under the pressure exerted by the sheet above and the free ends of the pile fibers are generally bent downwardly towards the carrier sheet. Consequently, many of the pile fibers invariably cross the path of the cutting blade as the layup is cut and portions of such pile fibers are cut off and disconnected from the remainder of the worksheet. When the cutting operation is complete, the bundles of pattern pieces are usually transported to a subsequent work site and during this transportation many of the disconnected fiber portions may fall loose or otherwise escape from the bundles into the work environment as dust. This dust is unsightly, may lodge in machinery, litter the floor and is generally objectionable in other ways.
In other types of cutting apparatuses layups of piled or fleecy sheets may be cut without a holddown or compression system. In such an arrangement, many of the pile fibers are cut but the number cut is usually fewer than the number cut by a cutting apparatus using holddown and compression, because the pile fibers in a non-holddown system are bent less during the cutting process than in the vacuum holddown system described above and therefore fewer pile fibers cross the path of the cutting blade. Also, if dies are used to cut a layup of piled or fleecy sheet material, pile fibers crossing the line of cut may be cut to create pile dust. Even if a single sheet of such material is cut by a reciprocating knife or die without a holddown system some pile fibers are cut although usually much fewer than are cut from a sheet in a layup of such material cut under compression.
The pile fibers and/or carrier sheets of piled or fleecy work sheets, such as velours, are often made of polyester or other thermoplastic material, as for example in the case where the pattern pieces are to be used for making automobile seats or other objects requiring highly-durable and washable coverings. However, for these and other applications, the fleecy worksheets may also be made of nonplastic materials such as cotton, wool or leather, or a combination of such materials.
Accordingly, a general aim of the invention is to provide an apparatus and method for cutting and dedusting plastic and nonplastic piled material, such as velour, which apparatus and method minimize the number of disconnected fibers which fall or otherwise escape from pattern pieces into the work environment as dust during or subsequent to the cutting operation.
Another object of the invention is to provide dedusting means for the foregoing apparatus which dedusting means does not appreciably interfere with an otherwise conventional cutting operation and which does not degrade the quality of the pattern pieces cut during the cutting operation.